This invention relates in general to processes for obtaining hydrocarbons from biomass, and more particularly to a hydrotreatment process for upgrading biomass pyrolyzates to feedstocks amenable to catalytic hydrotreatment for the production of gasoline-like fuels.
Biomass pyrolyzates do not, in general, contain a quantity or quality of hydrocarbons useful for automotive fuel or similar purposes. If these pyrolyzates are to become a useful source of hydrocarbons, they must be upgraded with additional processing such as catalytic hydrotreatment.
Unfortunately, biomass pyrolyzates are not easy to hydrotreat. When heated to typical hydrotreating temperatures, liquid biomass pyrolyzate oils tend to decompose, in a reaction that produces substantial heat, to form solid coke and non-hydrocarbon liquids.
This thermal instability problem of pyrolyzate oils has been demonstrated in numerous experiments.
We believe that undesired polymerization and coking of pyrolyzates during hydrotreatment may be caused by the presence of oxygen-containing compounds with carbonyl and ether bonds, and also by the presence of olefinic compounds.